Departamento de Tecnología Médica, Facultad de Medicina, Universidad de Concepción, Concepción, Chile.
Programa de Neurociencia, Psiquiatría y Salud Mental, NEPSAM (http://nepsam.udec.cl), Universidad de Concepción, Concepción, Chile.
PLoS One. 2023 Feb 22;18(2):e0282007. doi: 10.1371/journal.pone.0282007. eCollection 2023.
Brain-derived neurotrophic factor (BDNF) is essential for brain physiological processes influencing memory and learning. BDNF levels can be affected by many factors, including stress. Stress increase serum and salivary cortisol levels. Academic stress is of the chronic type. BDNF levels can be measure from serum, plasma or platelets, and there is still no standard methodology, which is relevant to ensure reproducibility and comparability between studies.
(i) BDNF concentrations in serum show greater variability than in plasma. (ii) In college students with academic stress, peripheral BDNF decreases and salivary cortisol increases.
To standardize plasma and serum collection for BDNF levels and to determine whether academic stress affects peripheral BDNF and salivary cortisol levels.
Quantitative research, with a non-experimental cross-sectional descriptive design.
Student volunteers. Under convenience sampling, 20 individuals will be included for standardization of plasma and serum collection and between 70 and 80 individuals to determine the effect of academic stress on BDNF and salivary cortisol.
PERIPHERAL BLOOD AND SALIVARY CORTISOL SAMPLING, MEASUREMENTS: 12 mL of peripheral blood (with and without anticoagulant) will be drawn per participant, separated from plasma or serum and cryopreserved at -80°C. Additionally, they will be instructed in the collection of 1 mL of saliva samples, which will be centrifuged. Val66Met polymorphism will be performed by allele-specific PCR, while BDNF and salivary cortisol levels will be determined by ELISA.
(i) descriptive analysis of the variables, through measures of central tendency and dispersion, and the categorical variables through their frequency and percentage. (ii) Then a bivariate analysis will be performed comparing groups using each variable separately.
We expect to (i) determine the analytical factors that allow a better reproducibility in the measurement of peripheral BDNF, and (ii) the effect of academic stress on BDNF and salivary cortisol levels.
脑源性神经营养因子（BDNF）是影响记忆和学习的大脑生理过程所必需的。BDNF 水平可受许多因素影响，包括压力。压力会增加血清和唾液皮质醇水平。学业压力属于慢性类型。BDNF 水平可从血清、血浆或血小板中测量，但目前仍没有相关的标准方法来确保研究之间的可重复性和可比性。
（i）血清中的 BDNF 浓度比血浆中的更具变异性。（ii）在有学业压力的大学生中，外周 BDNF 减少，唾液皮质醇增加。
标准化 BDNF 水平的血浆和血清采集，并确定学业压力是否会影响外周 BDNF 和唾液皮质醇水平。
定量研究，采用非实验性的横断描述性设计。
学生志愿者。采用便利抽样法，将纳入 20 名个体进行血浆和血清采集的标准化，纳入 70 至 80 名个体以确定学业压力对 BDNF 和唾液皮质醇的影响。
外周血和唾液皮质醇采样、测量：每名参与者抽取 12 毫升外周血（有抗凝剂和无抗凝剂），与血浆或血清分离并冷冻在-80°C。此外，还将指导他们采集 1 毫升唾液样本，然后对其进行离心。Val66Met 多态性将通过等位基因特异性 PCR 进行，而 BDNF 和唾液皮质醇水平将通过 ELISA 进行测定。
（i）通过集中趋势和离散度的测量以及通过其频率和百分比的分类变量，对变量进行描述性分析。（ii）然后将使用每种变量单独对组进行比较，进行双变量分析。
我们预计将（i）确定可提高外周 BDNF 测量重现性的分析因素，以及（ii）学业压力对 BDNF 和唾液皮质醇水平的影响。
